SB Nation's Jon Bois has statistically broken down how teams utilized running backs in 2010, and perhaps aided by the early-season presence of Marshawn Lynch, the Bills finished directly in the middle of the league in terms of how carries were split between running backs. By year's end, Fred Jackson was clearly Buffalo's workhorse, but the team still finished No. 16 overall in number of carries logged by their top runner. (The chart in question does not, however, account for the fact that the Bills also ran less than most teams.)
Even prior to drafting Spiller, the Bills had become a two-back offense, splitting carries between Lynch and Jackson for the better part of two seasons. Assuming Spiller is a bigger part of the offense heading into 2011, the Bills should place more emphasis on using two backs than ever before.